The Best Night

Lesson 19 of 20 in Coddy's Pygame Project: Hold the Keep course.

A survival game asks: how long did you last? Keep the longest night in a file, so it is still there next time the game opens:

def load_best():
    try:
        with open("best_night.txt") as file:
            return int(file.read())
    except (FileNotFoundError, ValueError):
        return 0

The first time the game runs there is no file: open raises FileNotFoundError, and except answers 0 instead of stopping the program. If the file holds something that is not a number, int raises ValueError, with the same answer.

When a night ends, compare it with the record once. night.saved remembers that this night was counted, because the loop keeps running after the end and would otherwise save every frame.

In the browser the file lasts while the page is open; on your own computer it stays next to main.py.

Challenge

Medium

Write load_best() above and save_best(frames), which writes str(frames) to best_night.txt.
Before night = Night(): best = load_best(). Give Night saved = False.
After the update: when the state is "won" or "lost" and the night is not saved yet, mark it saved, and if night.time is more than best, make it the best and save it.
Under the end message show f"You lasted {clock_text(night.time)}" at (360, 260) and f"Best night: {clock_text(best)}" at (360, 300).

Try it yourself

import random
import pygame

WIDTH, HEIGHT = 720, 480
TILE = 48
NIGHT = 60 * 60 * 4
BOSS_AT = NIGHT - 60 * 60
WAVES = [
    ["slime"],
    ["slime", "bat"],
    ["slime", "bat", "spider"],
    ["bat", "spider"],
    ["slime", "spider", "ghost"],
    ["bat", "spider", "ghost"],
    ["spider", "ghost"],
    ["bat", "ghost"],
]
UPGRADES = {
    "Quick bolts": "Bolts fire more often",
    "Sharp bolts": "Bolts hit harder",
    "Spinning axe": "One more axe circles you",
    "Swift boots": "You walk faster",
    "Gem magnet": "Gems come from further",
    "Hearty meal": "Get back a heart",
}
WHITE = (240, 240, 240)
BOLT = (120, 200, 255)
GOLD = (250, 200, 60)

pygame.init()
screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption("Hold the Keep")
clock = pygame.time.Clock()
font = pygame.font.Font("assets/fonts/pixel.ttf", 24)
small_font = pygame.font.Font("assets/fonts/pixel.ttf", 16)
big_font = pygame.font.Font("assets/fonts/pixel.ttf", 48)


def load(name):
    return pygame.image.load("assets/images/" + name).convert_alpha()


def sound(name):
    return pygame.mixer.Sound("assets/sounds/" + name)


def whiten(image):
    white = image.copy()
    white.fill((255, 255, 255), special_flags=pygame.BLEND_RGB_MAX)
    return white


floor_img = load("floor.png")
wall_img = load("wall.png")
knight_img = load("knight.png")
axe_img = load("axe.png")
gem_img = load("gem.png")
heart_img = load("heart.png")
empty_img = load("heart_empty.png")
MONSTERS = {
    "slime": {"image": load("slime.png"), "speed": 1.0, "hp": 1, "size": 28},
    "bat": {"image": load("dungeon_bat.png"), "speed": 1.6, "hp": 1, "size": 28},
    "spider": {"image": load("spider.png"), "speed": 1.2, "hp": 3, "size": 28},
    "ghost": {"image": load("ghost.png"), "speed": 0.8, "hp": 4, "size": 28},
    "boss": {"image": pygame.transform.scale(load("ghost.png"), (96, 96)), "speed": 0.7, "hp": 120, "size": 64},
}
hit_sound = sound("hit.ogg")
hurt_sound = sound("thud.ogg")
gem_sound = sound("coin.ogg")
level_sound = sound("powerup.ogg")

courtyard = pygame.Rect(TILE, TILE, WIDTH - 2 * TILE, HEIGHT - 2 * TILE)
background = pygame.Surface((WIDTH, HEIGHT))
for row in range(HEIGHT // TILE):
    for col in range(WIDTH // TILE):
        x = col * TILE
        y = row * TILE
        if courtyard.collidepoint(x, y):
            background.blit(floor_img, (x, y))
        else:
            background.blit(wall_img, (x, y))
cover = pygame.Surface((WIDTH, HEIGHT), pygame.SRCALPHA)
cover.fill((0, 0, 0, 150))
shade = pygame.Surface((WIDTH, HEIGHT), pygame.SRCALPHA)
dark_cover = pygame.Surface((WIDTH, HEIGHT), pygame.SRCALPHA)
dark_cover.fill((0, 0, 0, 210))


def draw(image, center):
    screen.blit(image, image.get_rect(center=center))


def clock_text(frames):
    seconds = frames // 60
    return f"{seconds // 60}:{seconds % 60:02d}"


def edge_point():
    side = random.randint(0, 3)
    if side == 0:
        return (random.randint(0, WIDTH), -24)
    if side == 1:
        return (random.randint(0, WIDTH), HEIGHT + 24)
    if side == 2:
        return (-24, random.randint(0, HEIGHT))
    return (WIDTH + 24, random.randint(0, HEIGHT))


class Knight(pygame.sprite.Sprite):
    def __init__(self):
        super().__init__()
        self.image = knight_img
        self.rect = pygame.Rect(0, 0, 24, 24)
        self.rect.center = courtyard.center
        self.speed = 3
        self.hearts = 5
        self.max_hearts = 5
        self.hurt = 0
        self.bolt_wait = 30
        self.bolt_damage = 1
        self.axes = 1
        self.magnet = 80

    def move(self, keys):
        if keys[pygame.K_LEFT]:
            self.rect.x -= self.speed
        if keys[pygame.K_RIGHT]:
            self.rect.x += self.speed
        if keys[pygame.K_UP]:
            self.rect.y -= self.speed
        if keys[pygame.K_DOWN]:
            self.rect.y += self.speed
        self.rect.clamp_ip(courtyard)


class Monster(pygame.sprite.Sprite):
    def __init__(self, kind, pos):
        super().__init__()
        self.kind = kind
        self.image = MONSTERS[kind]["image"]
        self.speed = MONSTERS[kind]["speed"]
        self.hp = MONSTERS[kind]["hp"]
        self.axe_wait = 0
        self.flash = 0
        self.pos = pygame.Vector2(pos)
        self.rect = pygame.Rect(0, 0, MONSTERS[kind]["size"], MONSTERS[kind]["size"])
        self.rect.center = self.pos

    def update(self, target):
        step = pygame.Vector2(target) - self.pos
        if step.length() > 0:
            self.pos += step.normalize() * self.speed
        self.rect.center = self.pos
        if self.axe_wait > 0:
            self.axe_wait -= 1
        if self.flash > 0:
            self.flash -= 1

    def hit(self, damage):
        self.hp -= damage
        self.flash = 6
        hit_sound.play()


class Bolt(pygame.sprite.Sprite):
    def __init__(self, start, target, damage):
        super().__init__()
        self.pos = pygame.Vector2(start)
        step = pygame.Vector2(target) - self.pos
        if step.length() == 0:
            step = pygame.Vector2(1, 0)
        self.velocity = step.normalize() * 7
        self.damage = damage
        self.rect = pygame.Rect(0, 0, 10, 10)
        self.rect.center = self.pos

    def update(self):
        self.pos += self.velocity
        self.rect.center = self.pos
        if not screen.get_rect().colliderect(self.rect):
            self.kill()


class Gem(pygame.sprite.Sprite):
    def __init__(self, pos):
        super().__init__()
        self.rect = pygame.Rect(0, 0, 24, 24)
        self.rect.center = pos
        self.rect.clamp_ip(courtyard)
        self.pos = pygame.Vector2(self.rect.center)

    def update(self, knight):
        target = pygame.Vector2(knight.rect.center)
        if self.pos.distance_to(target) < knight.magnet:
            self.pos.move_towards_ip(target, 6)
        self.rect.center = self.pos


class Night:
    def __init__(self):
        self.knight = Knight()
        self.time = 0
        self.monsters = pygame.sprite.Group()
        self.bolts = pygame.sprite.Group()
        self.bolt_timer = 0
        self.spin = 0
        self.gems = pygame.sprite.Group()
        self.xp = 0
        self.level = 1
        self.need = 5
        self.choices = []
        self.pick = 0
        self.boss = None
        self.state = "playing"

    def wave(self):
        return min(len(WAVES), self.time * len(WAVES) // NIGHT + 1)

    def spawn(self):
        wave = self.wave()
        if self.time % max(16, 46 - wave * 5) == 0:
            kind = random.choice(WAVES[wave - 1])
            self.monsters.add(Monster(kind, edge_point()))
        if self.boss is None and self.time >= BOSS_AT:
            self.boss = Monster("boss", (WIDTH // 2, -40))
            self.monsters.add(self.boss)
        boss = self.boss
        if boss and boss.alive() and boss.hp < MONSTERS["boss"]["hp"] // 2:
            if self.time % 120 == 0:
                for _ in range(3):
                    offset = (random.randint(-50, 50), random.randint(-50, 50))
                    self.monsters.add(Monster("bat", boss.pos + offset))

    def nearest(self):
        point = pygame.Vector2(self.knight.rect.center)
        best = None
        for monster in self.monsters:
            if best is None or point.distance_to(monster.pos) < point.distance_to(best.pos):
                best = monster
        return best

    def shoot(self):
        self.bolt_timer += 1
        target = self.nearest()
        if self.bolt_timer >= self.knight.bolt_wait and target is not None:
            self.bolt_timer = 0
            bolt = Bolt(self.knight.rect.center, target.pos, self.knight.bolt_damage)
            self.bolts.add(bolt)

    def axe_spots(self):
        spots = []
        for i in range(self.knight.axes):
            angle = self.spin + i * 360 / self.knight.axes
            offset = pygame.Vector2(70, 0).rotate(angle)
            spots.append(pygame.Vector2(self.knight.rect.center) + offset)
        return spots

    def hurt_monsters(self):
        for bolt in self.bolts:
            target = pygame.sprite.spritecollideany(bolt, self.monsters)
            if target is not None:
                target.hit(bolt.damage)
                bolt.kill()
        for spot in self.axe_spots():
            blade = pygame.Rect(0, 0, 36, 36)
            blade.center = spot
            for monster in self.monsters:
                if monster.axe_wait == 0 and blade.colliderect(monster.rect):
                    monster.hit(1)
                    monster.axe_wait = 20
        for monster in list(self.monsters):
            if monster.hp <= 0:
                monster.kill()
                drops = 8 if monster.kind == "boss" else 1
                for _ in range(drops):
                    self.gems.add(Gem(monster.pos))

    def collect(self):
        for gem in pygame.sprite.spritecollide(self.knight, self.gems, True):
            self.xp += 1
            gem_sound.play()
        if self.xp >= self.need:
            self.xp -= self.need
            self.level += 1
            self.need += 4
            self.choices = random.sample(list(UPGRADES), 3)
            self.pick = 1
            self.state = "levelup"
            level_sound.play()

    def upgrade(self, name):
        knight = self.knight
        if name == "Quick bolts":
            knight.bolt_wait = max(8, knight.bolt_wait - 8)
        elif name == "Sharp bolts":
            knight.bolt_damage += 1
        elif name == "Spinning axe":
            knight.axes += 1
        elif name == "Swift boots":
            knight.speed += 1
        elif name == "Gem magnet":
            knight.magnet += 40
        elif name == "Hearty meal":
            knight.hearts = min(knight.max_hearts, knight.hearts + 1)
        self.state = "playing"

    def take_hits(self):
        knight = self.knight
        if knight.hurt > 0:
            knight.hurt -= 1
        elif pygame.sprite.spritecollideany(knight, self.monsters):
            knight.hearts -= 1
            knight.hurt = 75
            hurt_sound.play()
            if knight.hearts <= 0:
                self.state = "lost"

    def update(self, keys):
        self.time += 1
        self.spin = (self.spin + 4) % 360
        self.knight.move(keys)
        self.spawn()
        self.monsters.update(self.knight.rect.center)
        self.bolts.update()
        self.gems.update(self.knight)
        self.shoot()
        self.hurt_monsters()
        self.collect()
        self.take_hits()
        if self.time >= NIGHT and self.state == "playing":
            self.state = "won"


night = Night()

running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYDOWN:
            if night.state == "levelup":
                if event.key == pygame.K_LEFT:
                    night.pick = (night.pick - 1) % 3
                elif event.key == pygame.K_RIGHT:
                    night.pick = (night.pick + 1) % 3
                elif event.key == pygame.K_SPACE:
                    night.upgrade(night.choices[night.pick])

    if night.state == "playing":
        night.update(pygame.key.get_pressed())

    screen.blit(background, (0, 0))
    knight = night.knight
    for gem in night.gems:
        draw(gem_img, gem.rect.center)
    for monster in night.monsters:
        if monster.flash > 0:
            draw(whiten(monster.image), monster.rect.center)
        else:
            draw(monster.image, monster.rect.center)
    if knight.hurt % 10 < 5:
        draw(knight.image, knight.rect.center)
    for spot in night.axe_spots():
        draw(pygame.transform.rotate(axe_img, -night.spin * 3), spot)
    dark = min(120, max(0, NIGHT - night.time) * 120 // (60 * 60))
    shade.fill((10, 10, 40, dark))
    screen.blit(shade, (0, 0))
    for bolt in night.bolts:
        pygame.draw.circle(screen, BOLT, bolt.rect.center, 5)
    for i in range(knight.max_hearts):
        if i < knight.hearts:
            screen.blit(heart_img, (8 + i * 34, 6))
        else:
            screen.blit(empty_img, (8 + i * 34, 6))
    left = font.render(clock_text(max(0, NIGHT - night.time)) + " until dawn", True, WHITE)
    screen.blit(left, left.get_rect(center=(WIDTH // 2, 24)))
    label = font.render(f"Level {night.level}", True, WHITE)
    screen.blit(label, label.get_rect(topright=(WIDTH - 10, 4)))
    pygame.draw.rect(screen, (40, 40, 60), (WIDTH - 160, 30, 150, 10))
    pygame.draw.rect(screen, GOLD, (WIDTH - 160, 30, 150 * night.xp // night.need, 10))
    if night.state == "levelup":
        screen.blit(cover, (0, 0))
        title = big_font.render("Level up! Pick one", True, GOLD)
        screen.blit(title, title.get_rect(center=(WIDTH // 2, 130)))
        for i, name in enumerate(night.choices):
            card = pygame.Rect(60 + i * 210, 190, 180, 120)
            pygame.draw.rect(screen, (40, 40, 60), card)
            if i == night.pick:
                pygame.draw.rect(screen, GOLD, card, 4)
            else:
                pygame.draw.rect(screen, WHITE, card, 2)
            text = font.render(name, True, WHITE)
            screen.blit(text, text.get_rect(center=(card.centerx, card.y + 40)))
            about = small_font.render(UPGRADES[name], True, WHITE)
            screen.blit(about, about.get_rect(center=(card.centerx, card.y + 80)))
        hint = font.render("Left and Right to choose, Space to take it", True, WHITE)
        screen.blit(hint, hint.get_rect(center=(WIDTH // 2, 360)))
    if night.state in ("title", "won", "lost"):
        screen.blit(dark_cover, (0, 0))
    if night.state in ("won", "lost"):
        if night.state == "won":
            message = big_font.render("Dawn! The keep holds", True, GOLD)
        else:
            message = big_font.render("The keep has fallen", True, WHITE)
        screen.blit(message, message.get_rect(center=(WIDTH // 2, 200)))
    pygame.display.flip()
    clock.tick(60)

pygame.quit()